Megasonic cleaner probe system with gasified fluid

#1. Field of the Invention

#The disclosure herein relates to an apparatus and method for cleaning semiconductor wafers or other such items requiring extremely high levels of cleanliness.

#2. Description of the Related Art

#Having thus summarized the general nature of the invention and its essential features and advantages, certain preferred embodiments and modifications thereof will become apparent to those skilled in the art from the detailed description herein having reference to the figures that follow, of which:

#FIG. 1 is a schematic view of a known probe-type megasonic cleaning system and an associated cleaning liquid supply system; and

#FIG. 2 is a schematic view of the inventive megasonic cleaning system.

#FIG. 1 depicts a known probe-type megasonic cleaning apparatus 10, generally comprising a tank-and-fixture assembly 12, a probe assembly 14 and a cleaning liquid supply system 15. The tank-and-fixture assembly 12 is made up of a tank 16 inside of which is disposed a fixture 18 adapted to support and/or securely hold a substrate 20, which may comprise a semiconductor wafer, photomask, flat-panel display, magnetic heads or any other similar item that requires a high level of cleanliness. The fixture 18 generally comprises a motor 22, shaft 24, hub 26, spokes 28, and an annular rim 30. The rim 30 supports and/or grips the substrate 20 as it is rotated about a generally vertical axis by the motor 22, in cooperation with the shaft, hub, spokes, etc. Upper and/or lower dispensers or nozzles 32, 34 spray a cleaning liquid onto the upper and/or lower surfaces of the substrate 20. A drain line 36 in the lower end of the tank 16 permits accumulated cleaning solution to exit therefrom.

#The probe assembly 14 comprises a megasonic probe 38 which is acoustically coupled to a megasonic transducer (not shown) inside of a probe housing 40. The housing 40 is mounted to a support member 42 so that the shaft of the probe 38 extends generally parallel to the surface of the substrate 20 and is separated therefrom by a narrow gap 44. The support member 42, along with the probe assembly 14, is retractable or rotatable upward to allow insertion/removal of substrates to the fixture 18. A slot 46 is provided in the tank 16 to permit rotational movement of the probe 38 in and out of the tank.

#In operation, high-frequency electrical power is supplied to the megasonic transducer, which vibrates at a high, megasonic frequency. This vibration is transmitted to the probe 38, which also vibrates at a megasonic frequency. The megasonic vibration of the probe 38 agitates the liquid on the substrate near the probe, creating a cleaning action on the surface of the substrate. Where the lower nozzle 34 is employed to provide cleaning liquid on the lower surface of the substrate 20, this lower-surface liquid is also agitated in the areas nearest the probe. As the substrate rotates under the probe, substantially the entire surface of the substrate is exposed to the cleaning action generated by the probe and agitated liquid.